Low programming voltage floating gate analogue memory cells in standard VLSI CMOS technology

Floating gate MOSFET structures were fabricated in a standard 2 mu m double-polysilicon CMOS process which requires programming voltages of only 6.5-9 V. This considerable reduction in programming voltage is achieved by simultaneously exploiting tunnelling through the interpolysilicon oxide and capacitive geometries whose top poly-layers overlap the edges of the lower poly-layers.